1. Field of the Invention
This invention relates to a foam regulator which, when used in detergent and cleaning preparations, is effective over a broad temperature range, i.e. suppressed troublesome foaming in the cold-wash range (20.degree. to 30.degree. C.), at medium washing temperatures (40.degree. to 60.degree. C.) and also in the boil-wash range. In addition, the foam regulator is stable in storage and in its effect in admixture with standard detergent ingredients and has no adverse effects either on the washed fabrics or on the environment.
2. Discussion of Related Art
Foam inhibitors based on paraffins and paraffin mixtures, including microcrystalline paraffins, suitable for use in detergents are known. To enhance their effect and, at the same time, to reduce the necessary in-use concentration, other known foam inhibitors, particularly polysiloxanes, polysiloxane/silica mixtures or bis-acylalkylenediamines derived from long-chain fatty acids (hereinafter referred to in short as bisamides), are often added to them. However, polysiloxanes are comparatively expensive and have the disadvantage that they hydrophobicize the fabrics or rather the surface of the treated items and that, in addition, they are largely resistant to biological degradation in the waste water. Accordingly, there is a further need to develop highly effective foam inhibitors which are free from silicon polymers.
The use of bisamides with paraffins as foam inhibitors for detergents is already known from German Patent Application, 20 43 087. However, the formulations mentioned therein do not have a uniform foam-inhibiting effect over a wide temperature range. Other preparations containing bisamides are known from European Patents 75 437 and 94 250. However, both contain silicones and cannot be considered for the reasons already mentioned. European Patent 87 233 describes a process for the production of a low-foaming detergent in which mixtures of an oily or wax-like substance and bisamides are applied to a powder-form substrate, more especially a spray-dried surfactant-containing detergent. The oily or wax-like substance may consist, for example, of petroleum jelly having a melting point of 20.degree. to 120.degree. C., and preferably 45.degree. to 65.degree. C. Mineral oil is used for this purpose in the examples There is no further differentiation of the wax-like constituent. It is quite clear that this component serves primarily as a support or dispersant for the bisamide Although satisfactory results are obtained in the Ross-Miles foam test where 2% by weight of a foam inhibitor mixture, based on the detergent, are used, these quantities appear far too large for practical purposes. In addition, it has been found that the blending technique used, i.e. spraying of the foam inhibitor onto the spray-dried surfactant-containing detergent, adversely affects the stability of the foam regulating component in storage, with the result that its activity decreases with increasing storage time.
Numerous other foam inhibitors containing bisamides as constituents are known. However, they are not specifically intended for use in detergents and cleaning preparations and, accordingly, do not show the desired temperature profile. In general, they contain silicones and/or emulsifiers and, hence, are attended by the described disadvantages. Examples of foam inhibitors such as these can be found in German Patents 21 41 905, 21 48 638, 24 04 210, 25 49 193, 29 44 604 and 30 08 952, and European Patent 56 160. Such foam inhibitors are used in the paper, sugar and textile industries and also for the defoaming of latices and drilling and cutting oil emulsions. These fields of application are not comparable with the special requirements of detergents and cleaning preparations.